The objective of the present invention is to provide an offset harrow of the hinged and wheeled type which possesses greater stability and ease of operation than the prior art.
More particularly, it is the object of the invention to improve the construction and mode of operation of the harrow disclosed in U.S. Pat. No. 4,308,919. That patent discloses an offset harrow of the hinged and wheeled type which is operated by a two element collapsible toggle linkage equipped with a power cylinder. It has been found that the two element toggle linkage provides somewhat less than the desirable stability of operation for the offset harrow and a less than adequately convenient arrangement for locking the forward and rear disc harrow units in their parallel transport positions. The present invention eliminates these drawbacks of the prior art by providing a very stable and reliable four element operating linkage connected between the forward and rear hinged carriers or harrow units. This improved linkage includes a support member or link for an adjustable latch or movement limiting bar which provides convenient and positive means of regulating the working angle between the forward and rear hinged harrow units through a desirable range of angles.
The improved linkage greatly facilitates locking the hinged harrow units in their parallel transport positions by rendering it much easier to insert and extract a locking pin through the latch bar support link and the adjacent front stablizer. The fact that the linkage elements are interengaged to support each other enables proper alignment of the holes which receive the linkage locking pin, thus achieving an improvement over the prior patented device where installation and extraction of a linkage locking pin proved to be difficult in many cases due to misalignment of pin receptor openings.
Still another object of the invention is to provide an offset harrow allowing for a plurality of working angles between the front and rear harrow disc carriers along with easier and more efficient means for setting the desired working angle between the carriers.
Still another object of the invention is to provide an efficient and reliable operating linkage for the hinged units of an offset harrow which is compactly arranged, and sturdy and durable.
Other features and advantages of the present invention will become apparent to those skilled in the art during the course of the following description .